for reference: I have two drives, one of which is system and the other is for user data, it is mounted in /share. I moved /usr/share to /share/usr/share with the command "mkdir -p /share/data/usr && cp -r /usr/share /share/data/usr/share && rm /usr/share && ln -s /share/usr /share/data/usr/share" after reboot everything worked as it should, except for man and file:
$ man man man: command exited with status 1: (cd /usr/share/man && /usr/lib/man-db/zsoelim) | (cd /usr/share/man && /usr/lib/man-db/manconv -f UTF-8:ISO-8859-1 -t UTF-8//IGNORE) | (cd /usr/share/man && preconv -e UTF-8) | (cd /usr/share/man && tbl) | (cd /usr/share/man && nroff -mandoc -rLL=193n -rLT=193n -Tutf8) $ echo $? 3 $ file /usr/bin/file /etc/magic, 4: Warning: using regular magic file `/usr/share/misc/magic' /usr/bin/file: data $ echo $? 0 $ cat /etc/os-release NAME="Ubuntu" VERSION="20.04.2 LTS (Focal Fossa)" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu 20.04.2 LTS" VERSION_ID="20.04" HOME_URL="https://www.ubuntu.com/"; SUPPORT_URL="https://help.ubuntu.com/"; BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"; PRIVACY_POLICY_URL=" https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"; VERSION_CODENAME=focal UBUNTU_CODENAME=focal
